I studied the survival and colonisation by ants of four different burned habitats in dunes along the coast of the Netherlands, using pitfall traps (tubes, Boer 2008) ten days after a fire, a few month after the fire, one, two and three years later, complemented with field observations.
Ants are chosen for this investigation because ants constitute the greatest part of the animal-biomass in those habitats. Other ground dwelling arthropods were present in the pitfalls, but in minute numbers.
Ants are organisms that directly or indirectly modify the availability of resources for other species by causing physical changes in biotic and abiotic material. By their construction of nests, perturbation of soils and interactions with many other organisms they are important ecosystem engineers and keystone species (Lach et al 2010).
Ants can be very sensitive to habitat transformation, and for this reason have been extensively used as indicator species (Lach et al 2010).
The fires were lit by one or more pyromaniacs.

Partly burned nest mound of the wood ant Formica rufa/polyctena, three weeks after the fire. Carex arenaria recoverd faster on the mound than in the surrounding area, v 2010.

Burned dune grassland, viii 2009.

Burned dune grassland, ix 2009.

Burned heathland, iv 2010.

Burned fire wood, viii 2009.

Three years after the fire, vii 2012.

Three years after the fire, x 2012.

Two and a half year after the fire, x 2012.

Three years after the fire, ix 2012.

DUNE GRASSLAND
Dune slope east of Vogelmeer, Schoorl; N 52.705 E 4.665
Burned on viii 2009.
Vegetation before the fire: The aspect was determined by Carex arenaria, Ammophila arenaria and Corynephorus canescens with spots of Calluna vulgaris and some shrubs of Prunus serotina (Koelerio-Corynephoretea).
Vegetation in 2012: not essential different of the situation before the fire, more patches with bare ground.

DUNE GRASSLAND
North of Bergerbos, Bergen NH; N 52.672 E 4.680
Burned on ix 2009.
Vegetation before the fire: The aspect was determined by Carex arenaria, Koeleria macrantha, Corynephorus canescens, Ammophila arenaria, moss and lichens (Koelerio-Corynephoretea).
Vegetation in 2012: not essential different of the situation before the fire but less developed, with more bare soil, without lichens.

HEATHLAND
Groot Ganzenveld, Schoorl; N 52.682 E 4.656
Burned on iv 2010.
Vegetation before the fire: The aspect was determined by Calluna vulgaris and Empetrum nigrum, some spots with moss, lichen, Carex arenaria and Corynephorus canescens.
Vegetation in 2012: The bottom was generally covered with a compact stratum of not burned but dead heather, alternated by bare spots covered by green algae and (young) moss. A vegetation of Calluna vulgaris and Rumex acetosella is developing, with little Carex arenaria and Erica tetralix and a few spots with Molinia caerulea.

Field observations
The wood ant mounds (Formica rufa/polyctena) in the centre of the heathland are all disappeared, maybe they removed to the wood edges with not burned oaks and birches. However, the number of woodant mounds along the wood edges was decreased, so the total number of wood ant mounds in and around the burned heather vegetation was decreased.

Other field observations in surrounding burned dune grasslands and heather vegetation
Only 4 % of all wood ant mounds Formica rufa/polyctena were completely burned (n=222). The mounds in the burned area were partly destroyed; mean 38 % of the mound. From the Formica exsecta mounds this was 47 % (n=19), 10 % were completely burned.
After two and a half year 60 % of the Formica rufa/polyctena mound populations proved to have survive it, of wich 47 % had move their mound.
The effect of fire on wood ant mounds was more far-reaching after a fire a month later in time of the year (May 2011). Here 35 % of the wood ant mounds Formica rufa/polyctena (n=57) extinct after the fire. Only one of the more than 20 mounds of Formica exsecta survived. The lack of food after the fire in this essential time of the year must be the cause of it.

PINE WOOD
East of Vogelmeer, Schoorl; N 52.711 E 4.672
Burned on viii 2009.
Vegetation’s before the fire: Pinus nigra, with ground vegetation of only moss.
Vegetation in 2012: No living trees and shrubs. Sand covered by green algae and young moss vegetation. A few spots with Calamagrostis epigejos and Chamerion angustifolium.

-Lasius psammophilus takes advantage of the decline of other ant species and the transformation in new dune habitats.

-Directly after the fire the mounds of mound building ants like Formica rufa/polyctena and F. exsecta were heavily damaged, but seldom extinct, except if the fire occurs in late spring. Due to the food storage at least 47 % of the wood ants Formica rufa/polyctena moved their mounds more than ten meters. After two and a half year 60 % of the mounds survived.

- The extinction of Lasius meridionalis mounds is still a not solved issue.

Lasius platythorax nest in burned pine stump. The nest population (partly) survived the fire, but died due to lack of food. ix 2009.

Discussion
-The situation of the ant population as whole three years after the fire, must be symptomatically for the total bottomfauna. In other words, the bottomfauna as whole must be decreased
too and recovery will take years.

-Due to the fact that ants are essential for seed dispersal of many plant species, the diversity of the vegetation can only be optimal as the ant fauna is recovered.

- Treading of the soil by cattle, especially by sheep, has as consequence compaction of the soil. This is a negative development on the recovery of the ant fauna and obstructs the recovery of an optimal vegetation.